TBC Metalworks is a CNC mandrel tube bending shop in Green Bay, Wisconsin. We bend round tube, pipe, square and rectangular tube, and solid rod to your drawing, then cut, end form, weld and polish in-house so the part ships complete. We have bent tube in Green Bay since 1987 and ship custom bent parts across the United States.
What is CNC mandrel tube bending?
Mandrel bending, also called rotary draw bending, clamps the tube to a bend die and draws it around the die. For thinner wall and tighter radius bends, a mandrel inside the tube and a wiper die on the inside of the bend support the wall, which keeps the tube round and prevents wrinkling. That makes it the right process for tight radii, thin walls, and parts with several bends in different planes. Rotary draw bending is typically used for centerline radii under about 12″. For larger, sweeping radii we use tube roll bending.
Mandrel bending size range
| Material form | Size range |
|---|---|
| Round tube | 1/8″ to 3″ OD (CNC mandrel: 1/2″ to 3″) |
| Pipe (rotary draw) | 1/4″ to 2-1/2″ NPS |
| Square and rectangle tube | 5/8″ to 2″ square; rectangles from 3/4″ x 1-1/2″ to 3″ x 1-1/2″ |
| Solid rod | 1/8″ to 2″ |
| NC tube and pipe bending | 1/2″ to 3″ tube, 1/2″ to 2-1/2″ pipe |
Centerline radius (CLR) tooling on hand
We keep a large library of bend tooling, which keeps tooling cost and lead time down. Designing your part around a radius we already have is the easiest way to avoid new tooling. Radii are centerline radius (CLR) unless noted. This is a general list and may not include all of our dies, so contact us for the latest.
Round tube
| Tube OD | Bend radii dies |
|---|---|
| 1/8″ | 0.5625″ |
| 3/16″ | 0.5625″ |
| 1/4″ | 0.5625″, 0.625″ |
| 3/8″ | 0.625″, 1.125″, 2.1875″ |
| 1/2″ | 0.75″, 1.25″, 1.5″ |
| 5/8″ | 1.25″, 1.5″, 2″, 3.5″ |
| 3/4″ | 1.35″, 1.5″, 1.875″, 1.9375″, 2″, 2.12″, 2.5″, 3″, 3.375″, 6.5″ |
| 0.78″ | 6.5″ |
| 22 mm (0.866″) | 76 mm (2.992″), 3.06″ |
| 7/8″ | 2″, 2.5″, 3″ |
| 1″ | 1.5″, 2″, 2.5″, 3″, 3.438″, 3.5″, 3.78″, 4.5″, 5.09″, 6.53″, 7″ |
| 1-1/8″ | 2.375″ |
| 1-1/4″ | 2″, 2.25″, 2.375″, 2.5″, 3″, 3.125″, 3.5″, 4″, 4.5″, 5″, 6″ |
| 1-1/2″ | 1.5″, 2″, 3″, 4″, 4.25″, 4.5″, 5″, 6″ |
| 1-5/8″ | 4″ |
| 1-3/4″ | 3″, 4″, 5.25″ |
| 2″ | 2″, 2.75″, 3.81″, 4″, 5.5″, 6″, 8″, 12″ |
| 2-1/2″ | 5″ |
| 3″ | 7″, 9″ |
Pipe
| Pipe size (NPS) | Pipe OD | Bend radii dies |
|---|---|---|
| 1/4″ | 0.54″ | 1.5″ |
| 3/8″ | 0.675″ | 2.5″, 3.5″ |
| 1/2″ | 0.84″ | 1.5″, 2″, 3″ |
| 3/4″ | 1.05″ | 2″, 2.5″, 3″, 3.75″, 4.25″, 5.5″ |
| 1″ | 1.315″ | 1.5″, 2″, 3″, 4″, 5″, 7″ |
| 1-1/4″ | 1.66″ | 2.5″, 2.83″, 3″, 3.9″, 4″, 5″, 5.75″ |
| 1-1/2″ | 1.9″ | 3.75″, 3.9″, 6″, 6.75″ |
| 2″ | 2.375″ | 3″, 5.118″, 6″, 7″, 7.87″, 8.375″, 8.69″, 9″, 10″, 12″ |
| 2-1/2″ | 2.875″ | 3.75″, 6″, 6.875″, 10″ |
Square and rectangle tube
| Profile | Bend radii dies |
|---|---|
| 5/8″ square | 8″ |
| 1″ square | 2.5″, 4.5″, 4.625″, 6.5″ |
| 1-1/4″ square | 3.125″, 3.625″, 4.625″ |
| 1-1/2″ square | 3.75″, 3.95″, 4″, 5″, 6.15″ |
| 2″ square | 4.5″, 7″ |
| 3/4″ x 1-1/2″ rectangle | 6.625″ |
| 1″ x 1-1/2″ rectangle | 3.54″ IR |
| 1″ x 2″ rectangle | 3.5″, 4.5″, 6″ |
| 1-1/4″ x 2″ rectangle | 2.75″ IR |
| 1-1/2″ x 2″ rectangle | 2.95″ IR |
| 1-1/2″ x 2-1/2″ rectangle | 3.75″ |
| 2″ x 1″ rectangle | 4″ |
| 2-1/2″ x 1-1/2″ rectangle | 2″ IR, 5″ IR |
| 3″ x 1-1/2″ rectangle | 8.875″ |
Rectangle radii marked IR are inside radius; all other radii are centerline radius (CLR). Tell us the bend direction (easy way or hard way) on rectangle parts and we will confirm which die fits.
Don’t see your size or radius? Send the drawing anyway. We add tooling for production programs, and radii larger than about 15″ are usually roll bent without dedicated tooling.
Materials we bend
- Carbon steel: A500, A513, A53, DOM and ERW tube and pipe
- Stainless steel: 304 and 316
- Aluminum: 6061 and 6063
- Copper
- Plus other materials as needed
Typical bent tube parts
- Lawn mower and zero-turn handles
- Farm, agriculture and construction equipment tubes
- Medical and industrial cart frames
- Commercial and loader handrails
- Bus and transportation components
- Fitness equipment frames
- Military vehicle tubes
- Car wash and machine components
See more on our product examples page.
Finishing the part in-house
Most bent tubes need more than a bend. We also do:
- CNC bandsaw cutting to length
- Tube end forming and swaging: expanding, reducing, flaring, beading and flattening
- Coping and notching, threading and tapping, and CNC machining of holes and slots
- MIG and TIG welding
- Stainless and aluminum polishing
- Laser cut plates, powder coating and anodizing through long-term local partners
Volumes and lead time
We run prototypes through production, and we are set up for programs of 50 to 10,000+ units per year. Projects can ship in as little as one week. Minimum order: generally about 10 pieces.
Get a mandrel bending quote
Send a PDF drawing, a STEP file or 3D model if you have one, the material, and your annual volume through our quote form or to sales@tbcmetalworks.com. We reply with a quote within one business day. Not sure which process fits your part? Read mandrel bending vs. roll bending or see our tube bending FAQ.